----- Original Message -----
>From: "Bruce Stallsmith" <fundulus at hotmail.com>
>I'd guess that in an aquarium they'd prefer to take food coming at them in
a current.

The specimens I've been maintaining have prefered low current areas adjacent
to high current areas where food collects. They rarely take it on the
fly... They seem to prefer to let it settle into areas where sand has
accumulated on the surface, and then take it from there. Again, it would be
an interesting study to find what the role of "terra"-phagy is in their
physiology.

The specifics involved are really just the hydrodynamics of the particular
"pool-adjacent riffle" as to where what and when... They certainly won't
work for their food in the column, but will move pounds of substrate instead
to get at it. So I have to feed enough to satiate cyprinids etc so that
food does collect on the areas where the suckers will graze. And again, I'm
using extremely high quality food, and a LOT of it.

Which is another reason the sand is so beneficial. I can dump 2 oz of food
into my 100 gallon at one serving and not cause a massive ammonia spike.
Which gets me to....

I'm not sure if this is past experience or just a regurgitation from the
"aquarium hobby", but in the two years I've systematically worked with deep
sand in freshwater aquaria (hey it's two years this month! :), I've found it
nothing but beneficial, rather than a hinderance. I've neither damaged
equipment nor made a mess of the aquarium. Biofilms hold the granules in
place, and even with a "vaccum cleaner" like a hog sucker, it settles right
on back down where it belongs. It usually takes two weeks for a strong
biofilm to set up. After that, you're good to go.

Oh, and it's self cleaning. It will actually "consume" detritus, even more
quickly if it's seeded with live substrates from a stream. For example, the
30 gallon that I just moved to the Reef-le (tm) and in the process, ripped
out all the valiserna to easily capture the fish. It stirred all sorts of
mulm, which settled to the sand surface. The tank sat empty for two
weeks... There's very little mulm left, to which I responded by adding a
grass pickerel and his emerald shiner "buffet". I didn't want to drop the
carrying capacity for all those fly little microcrustraceans I see flitting
around :)

...And I'm glad to say that they existed in a very heavily stocked 30 gallon
with a minimum of 30 darter specimens. You can create predator free space
in the aquarium. How neat.

There's a lot of my posts about this on the list archive if you'd like to
read more about the progression and gained knowledge of this topic. I've
documented the good, the bad and the ugly pretty well on the list. The
archive is found at: http://www.nanfa.org/archive/nanfa/

Ugggghhh... Back to my Lotka Volterra misery. What is all this math crap? I
thought I was studying fish. ;)

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